搜索

[Javascript] Multiply Two Arrays over a Function in JavaScript


发布时间: 2022-11-24 18:12:01    浏览次数:13 次

Just like the State ADT an Array is also an Applicative Functor. That means we can do the same tricks with liftA2 with Array that we have been doing with State.

While the Applicative aspect of State allows use to combine multiple stateful transitions over a function, Array allows us to create a new Array that contains the results of calling every permutation of each element in two arrays over a function. We will use this ability to pull from two separate locations in our AppStateand generate an Array of Cards.

liftA2 from crocks.js "Ever see yourself wanting to map a binary or trinary function, but map only allows unary functions? Both of these functions allow you to pass in your function as well as the number of Applicatives (containers that provide bothof and apfunctions) you need to get the mapping you are looking for."

lift from Ramda.js "lifts" a function of arity > 1 so that it may "map over" a list, Function or other object that satisfies the FantasyLand Apply spec.

// Crocks.js

const buildCard = curry((color, shape) => console.log(color, shape) || ({
    id: `${color}-${shape}`,
    color,
    shape
}));
// buildCards :: [String] -> [String] -> [Card]
const buildCards = liftA2(buildCard);


// Ramda.js

const build = lift(buildCard);

 --- 

const {prop,assoc, pick, State, identity, omit, curry, filter, converge,map, composeK, liftA2, equals, constant,option, chain, mapProps, find, propEq, isNumber, compose, safe} = require('crocks');
const  {get, modify, of} = State; 
const {lift} = require('ramda');

const state = {
    colors: [ 'orange', 'green', 'blue', 'yellow' ],
    shapes: [ 'square', 'triangle', 'circle' ]
  };

const getState = (key) => get(prop(key))
const getColors = () => getState('colors').map(option([]));
const getShapes = () => getState('shapes').map(option([]));

const buildCard = curry((color, shape) => console.log(color, shape) || ({
    id: `${color}-${shape}`,
    color,
    shape
}));
// buildCards :: [String] -> [String] -> [Card]
const buildCards = liftA2(buildCard);
const generateCards = converge(
    liftA2(buildCards),
    getColors,
    getShapes
)
console.log(
    generateCards()
        .evalWith(state)
)

const build = lift(buildCard);
console.log('build', build([1,2,3], ['c', 'd']))

 

免责声明 [Javascript] Multiply Two Arrays over a Function in JavaScript,资源类别:文本, 浏览次数:13 次, 文件大小:-- , 由本站蜘蛛搜索收录2022-11-24 06:12:01。此页面由程序自动采集,只作交流和学习使用,本站不储存任何资源文件,如有侵权内容请联系我们举报删除, 感谢您对本站的支持。 原文链接:https://www.cnblogs.com/Answer1215/p/10277748.html